An example of one type of lamp is described in Japanese utility model publication No. 22633/1982. The lamp of Japanese Publication No. 22633/1982 includes a pair of sockets for a bulb, each socket comprising a U-shaped bent plate having a bottom in the middle and a pair of mutually facing legs or squeezing pieces on both sides thereof. Each of the squeezing pieces have a mounting bore therethrough. A base body having a pair of spaced socket-insertion bores formed therethrough is also provided such that each socket-insertion bore include pair of protrusions extending inward from opposite inner walls thereof. These protrusions are adapted to being snap-fit in the mounting bores formed through the pair of squeezing pieces. A switch lever is pivoted to the base body and a resilient piece forming a switch mechanism has one end fixed to the base body between either the socket or the switch lever, with its other end adapted to being brought into contact with one of the squeezing pieces of one of the sockets by the action of the switch lever.
In the above-described prior art lamp, which has been developed mainly for use as an interior room lamp of an automobile, the switch lever projects from the base body horizontally relative to the flat base body face. The base body adapted to mounting a bulb of the lamp thereon. The switch lever, furthermore, is pivotal. As such, the prior art lamp described above is not suitable for use as a trunk lamp which needs to be activated in response to the opening/closing of a trunk hood so as to illuminate the interior of the trunk. Moreover, the structure of the lamp switch is such that it may be broken by large forces associated with the opening or closing of the trunk hood.